Furnace for steam-boilers.



F. DUFFY.

FURNAGB FOR STEAM BOILERS.

APPLICATION FILED MAR. 2, 1910.

Patented Nov. 29, 1910.

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FRANCIS DUFFY, OF CHICAGO, ILLINOIS.

FURNACE FOR STEAM-BOILERS.

Specification of Letters Patent.

Patented Nov. 29, 1910.

Application filed March 2, 1910. Serial No. 546,818.

To all whom t may concern:

Be it known that I, F minors DUFFY, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Furnaces for Steam-Boilers, of which the following is a speciication.

My invention relates to furnaces for steam boilers especially locomotiveboilers and the object of the invention is to provide simple andefficient means for pre-heating and oxidizing the air entering into thefire box.

I accomplish my objects by employing a y construction the preferred formof which is shown in the accompanying drawings, in which:

Figure l is a front elevation of a boiler furnace embodying myinvention, Fig. 2 is a longitudinal sectional elevation taken on theline 2-2, Fig. l, and Fig. 3 is a detail, drawn to an increased scaleshowing the most important parts of my invention. The plane of sectionof Fig. 3 is the same as that of Fig. 2.

Similar letters refer to similar parts throughout the several views.

Referring to the accompanying drawings, the fire box a is provided withgrate bars o, and communicates with iire tubes c. Between the front walla of the fire box and the front wall el of the boiler d is a space ewhich contains water. As the water in this space is adjacent to the rebox it will remain at a temperature approximately the same as thetemperature of the water in the other parts of the boiler. There is anopening e in the front of the boiler passing through the walls a and dfor the introduction of coal and air into the fire box.

Secured tothe front of the boiler surrounding the opening e is apre-heating chamber having a front wall f and peripheral walls f. Saidchamber has a door frame formed of walls f2 arranged to register withthe opening e in the boiler front, these walls in the preferredconstruction being of cast metal integral -with the por` tions f and f.The frame is provided with a door g of ordinary construction.

rIhe peripheral walls, f of chamber f are apertured to admit of airbeing drawn into said chamber from all parts of the periphery thereof.Apertures f3 are formed in the walls f2 and permit the air to pass fromthe chamber f into the .door frame. By preference there is also a space7L at the rim of the door frame which permits the air to pass directlyfrom the chamber f into the opening e.

At the inner margin of the door frame is formed a duct or passage z'from which a number of small openings lead inwardly to the lire boxthrough the opening e. Said duct is for the purpose of introducing steamwhich is furnished through a supply pipe j shown in Fig. 1.

In operation the draft through the fire box causes air to be drawn intothe chamber f through the apertures in the peripheral walls thereof,this air being finally drawn into the fire box through the apertures f3and opening e. As the water in the space e keeps the boiler front d at ahigh temperature, the air thus passing through the chamber f is heatedby contact with said boiler front and therefore enters into the openinge at a high temperature thus furnishing oxygen to the gases in the firebox in a heat ed condition. As a result the combustion is rapid andcomplete and the production of smoke is prevented. The chamber f thusconstitutes a pre-heating chamber which enables air to be introduceddirectly into the fire box without chilling the gases and producingsmoke but on the contrary prevents the formation of smoke. The metaladjacent to the duct z' will be kept at a high temperature as a resultof exposure to the heat of the iire box and hence said metal willsuperheat the steam entering the opening e through the apertures Z. Thissuper-heated steam, meeting the preheated air in the opening e" willcause a thorough commingling of heated air and steam prior to entranceinto the fire box, with the result that a liberal supply of oxygen willbe introduced into the lire box in heated condition, thus efiicientlypromoting combustion.

I claim as my invention l. In combination, a steam boiler having asubstantially flat front through which there is an opening leading intothe fire box, and a shallow dished preheating chamber secured to theboiler front surrounding said opening and communicating therewith andcontacting the boiler front at its periphery, the boiler front formingthe back of the preheating chamber, and said preheating chamber havinginlets for air at its edges whereby the draft Will draw air through saidchamber across the boiler front before entering the fire boX.

2. In combination, a steam boiler having a tire-box and an opening inthe front leading thereinto, and a iiat preheating chamber secured tothe boiler front surrounding said opening and communicating therewith,said preheating chamber having inlets for air at its edges and having asteam duct With apertures arrangedaround kthe margin of said opening forthe purpose described.

3. In combination, a ysteam boiler having a fire-box and an openinginthe front leading thereinto, a steam duct arranged around the marginof said opening andhaving apertures leading thereinto, and a flatpreheating chamber securedto the front of the boiler, and discharginginto the boiler adj acent to the steam duct, substantially as described.

4. In combination, a steam boiler, having a fire-box and an opening inthe i'front leading thereinto, and a flat preheating chamber secured tothe boiler front surrounding said opening and communicating therewith,said preheating chamber consisting of cast metal and having a ductformed in the metal and arranged to extend around the margin of saidopening Where it will be exposed to the heat of the fire in the firebox, there being` small steam outlets leading from said duct intosaidopening, substantially as described.

In Witnesswhereof, I have hereunto subscribedv my name in the presenceof two Witnesses.

FRANCIS DUFFY. Vitnesses HOWARD M. COX, MARGARET I). Bonn.

